This invention relates to an apparatus for injecting an accelerating fuel and more particularly to an improved acceleration fuel delivery system and method for the induction system of an internal combustion engine.
As is well known, it is desirable to provide some form of accelerating fuel delivery system for an engine for delivering extra fuel under acceleration conditions, when the engine throttle is rapidly opened. Because of the greater weight of the fuel, the mixture strength tends to lean during rapid opening of the throttle valves. That is, the less dense air can accelerate more rapidly than the heavier density fuel and unless additional fuel is provided, a lean mixture and poor acceleration will result. For this reason, it is a common practice to provide an accelerating pump that is operated in response to opening movement of the throttle valves so as to inject additional fuel into the induction air stream.
Although such acceleration pump arrangements aid in improving performance under acceleration, conventional accelerating pumps do not fully supply the needs of the engine during acceleration. That is, because the accelerating pump is responsive to the movement of the throttle valve rather than the actual demand of the engine, conventional accelerating pumps tend to inject excess fuel at the initiation of the acceleration mode and insufficient fuel at the end of the acceleration rode. Furthermore, the opening of the throttle valve under acceleration conditions does not truly represent the actual change in engine speed and/or the actual change in performance of the associated vehicle. That is, even though the throttle valves may be opened rapidly, the engine speed and the speed of the associated vehicle accelerate less rapidly. Therefore, the conventional type of acccelerating pump generally supplies more fuel than is necessary at the initiation of the acceleration mode and less fuel than is required at the end of the acceleration period.
It has been proposed, therefore, to incorporate an accelerating pump in which a spring is interposed between the throttle actuated member and the pumping member of the accelerating pump. With such an arrangement, the spring is loaded during initial opening of the throttle valve and the accelerating pump pumping member is operated with a delayed action. Such an arrangement tends to reduce the amount of fuel delivery during initial throttle opening and have the fuel delivery delayed for a period of time. Although such an arrangement appears to be feasible, in practice it does not solve the problems as aforenoted. Furthermore, it is extremely difficult to provide an accurate calibration for the spring and relate the movement of the accelerating pump pumping member to the throttle valve when a spring is interposed between these members. As a result, poor performance on acceleration can result.
It is, therefore, a principle object of this invention to provide an improved accelerating fuel delivery system for an internal combustion engine.
It is a further object of this invention to provide an accelerating pump in which the fuel delivery is more directly related to the actual requirements of the engine.
It is a further object of this invention to provide a improved method for delivering fuel to an engine during the acceleration mode.
It is a further object of this invention to provide an accelerating fuel delivery method that is directly related to the engine requirements.